NEET · Biology · STD 11 - 8. Cell the unit of life

The structures that help some bacteria to attach to rocks and/or host tissues are

A mesosomes
B holdfast
C rhizoids
D fimbriae.

Verified Solution

Answer & Solution

Correct Answer

(D) fimbriae.

Step-by-step Solution

Detailed explanation

(d) : Fimbriae are small bristle like solid structures arising from bacterial cell surface. There are \(300-400\) of fimbriae per cell. Their diameter is \(3-10\ nm\) while length is \(0.5-1.5\ \mu m\). Fimbriae are involved in attaching bacteria to solid surfaces ( \(e.g.\), rock in water body) or host tissues ( \(e.g.\), urinary tract in Neisseria gonorrhoeae). Some fimbriae cause agglutination of \(RBCs\). They also help in mutual clinging of bacteria.

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Select the correct option. Column I - Column II

Column \(I\)	Column \(II\)
(A) Synapsis aligns homologous chromosomes	(i) Anaphase \(II\)
(B) Synthesis of \(RNA\) and protein	(ii) Zygotene
(C) Action of enzyme recombinase	(iii) \(G_2\) phase
(D) Centromeres do not separate but chromatids move towards opposite poles	(iv) Anaphase \(I\)
	(v) Pachytene

NEET 2015 Medium

Match the following enzymes with their functions

\((a)\) Restriction endonuclease	\((i)\) Joins the \(DNA\) fragements
\((b)\) Restriction exonuclease	\((ii)\) Extends primers on genomic \(DNA\) template
\((c)\) \(DNA\) ligase	\((iii)\) Cuts \(DNA\) at specific position
\((d)\) Taq polymerase	\((iv)\) Removes nucleotides from the ends of \(DNA\)

Select the correct option from the following

NEET 2019 Medium

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